Background

Burdock has historically been used to treat a wide variety of ailments, including arthritis, diabetes, and hair loss. It is a principal herbal ingredient in the popular cancer remedies Essiac® (rhubarb, sorrel, slippery elm) and Hoxsey formula (red clover, poke, prickly ash, bloodroot, barberry).

Burdock fruit has been found to lower blood sugar in animals, and early human studies have examined burdock root in diabetes. Laboratory and animal studies have explored the use of burdock for bacterial infections, cancer, HIV, and kidney stones. However, there is currently insufficient human evidence regarding the efficacy of burdock for any indication.

Evidence

DISCLAIMER:
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Diabetes:
Animal research and initial human studies suggest possible blood sugar lowering effects of burdock root or fruit. However, the available human research has not been well designed, and further study is needed before a clear recommendation can be made.
Grade: C

Quality of life in cancer patients (breast cancer):
Burdock is an ingredient in the popular purported cancer remedy, Essiac®. Preliminary study has shown that burdock may have anti-cancer effects and increase quality of life in cancer patients. More study is needed in this area.
Grade: C

Dosing

Adults (18 years and older)

No specific dose of burdock has been proven effective or safe, although a range of doses and types of preparations have been used. As a dried root, tablets/capsules, decoctions, tinctures, fluid extract, and root teas are available. Burdock has been used as a diuretic (to increase urine flow) with preparations made from powdered burdock seeds into a yellow product called oil of lappa.

Burdock has been used on the skin as a compress or plaster for eczema, psoriasis, baldness, and warts.

Children (younger than 18 years)

There is not enough scientific information to recommend the use of burdock in children.

Safety

DISCLAIMER:
Many complementary techniques are practiced by healthcare professionals with formal training, in accordance with the standards of national organizations. However, this is not universally the case, and adverse effects are possible. Due to limited research, in some cases only limited safety information is available.

Allergies

Allergy to burdock may occur in individuals with allergy to members of the Asteraceae/Compositae family, including ragweed, chrysanthemums, marigolds, and daisies. Severe allergic reactions (anaphylaxis) have been associated with burdock. Allergic skin reactions have been associated with the use of burdock plasters on the skin. Caution should be used in patients with allergies or intolerance to pectin since certain parts of the burdock plant contains different levels of pectin complex.

Side Effects and Warnings

Based on traditional use, burdock is generally believed to be safe when taken by mouth in recommended doses for short periods of time. Handling the plant or using preparations on the skin (such as plasters) has occasionally been reported to cause allergic skin reactions. Diuretic effects (increasing urine flow) and estrogen-like effects have been reported with oral burdock use in patients with HIV. Although reports of symptoms such as dry mouth and slow heart rate have been noted in people taking burdock products, it is believed that contamination with belladonna may be responsible for these reactions. Contamination may occur during harvesting.

In theory, tannins present in burdock may be toxic, although toxicity has not been reported in animal studies. Tannins can cause stomach upset and in high concentrations may result in kidney or liver damage. Long-term use of tannins may increase the risk of head and neck cancers, although this has not been seen in humans. Based on animal research and limited human study, burdock may cause increases or reductions in blood sugar levels. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Blood sugar levels may need monitoring by a qualified healthcare provider, and medication adjustments might be necessary. In theory, burdock may also cause electrolyte imbalances (for example, changes in potassium or sodium levels in the blood) due to diuretic effects (increased urine flow).

Several case reports of burdock root tea poisoning exist along with cases of burdock ophthalmia (eye inflammation). There have been several reports of stomatitis (mouth sores) present in dogs that have come in contact with burdock, burs, and bristles.

Pregnancy & Breastfeeding

Based on animal studies that show components of burdock to cause uterus stimulation, burdock is sometimes recommended to be avoided during pregnancy. Due to limited scientific study, burdock cannot be considered safe during pregnancy or breastfeeding.

Interactions

Interactions with Drugs

Based on animal research and limited human study, burdock may either lower or raise blood sugar levels. Caution is advised when using medications that may also affect blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare provider. Medication adjustments may be necessary. Burdock has been associated with diuretic effects (increasing urine flow) in one human report and in theory may cause excess fluid loss (dehydration) or electrolyte imbalances (for example, changes in potassium or sodium levels in the blood). These effects may be increased when burdock is taken at the same time as diuretic drugs such as chlorothiazide (Diuril®), furosemide (Lasix®), hydrochlorothiazide (HCTZ), or spironolactone (Aldactone®). Based on limited human evidence that is not entirely clear, burdock may have estrogen-like properties and may act to increase the effects of estrogenic agents including hormone replacement therapies such as Premarin® or birth control pills.

Medications taken to treat gout, cancer, or HIV may interact with burdock. There is also a possible interaction with antibiotics.

Interactions with Herbs and Dietary Supplements

Based on animal research and limited human study, burdock may either lower or raise blood sugar levels. Caution is advised when using herbs or supplements that can also alter blood sugar. Blood glucose levels may require monitoring, and doses may need adjustment.

Burdock has been associated with diuretic effects (increasing urine flow) in one human report, and in theory, may cause excess fluid loss (dehydration) or electrolyte imbalances (for example, changes in potassium or sodium levels in the blood) when used with other diuretic herbs or supplements.

Based on animal research, burdock may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, fewer cases with garlic, and two cases with saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Herbs or supplements taken to treat gout, cancer, or HIV may interact with burdock. There is also a possible interaction with herbs with antibacterial, antioxidant, or anti-inflammatory effects (such as ginger).

Bibliography

DISCLAIMER:
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

Anonymous. In vitro screening of traditional medicines for anti-HIV activity: memorandum from a WHO meeting. Bull World Health Organ 1989;67(6):613-618.